I really don’t understand why you would want to keep mystery heroes the way it is. Currently the way it works is that the team that is lucky enough to get a functioning team composition wins.
There’s absolutely no skill involved. Simply luck of the draw which team wins. What is so fun about that?

Having randomized heroes is a good idea.
Having purely randomized heroes, with no rules on team composition can get to feel like whichever team has the best RNG automatically wins. Killing the fun of this gamemode.
But there are some easy rule fixes on next-spawns:
If a team has 3x healers, don’t spawn more healers.
If a team has 0x healers, next spawn is 100% a healer.
If the team has 2x self-heal non-healer, don’t spawn any more. (These are overpowered in this mode).
If one team has a Phar…

Enough people here in the thread saying the same thing, with Jeff himself saying he understands why.

There’s no way to convince people like you, because you always say the same thing, just like how we’ll always say remove hero stacking.

Least they can do is try a mode, separate from MH which is “limited MH” with non-hero stacks.

Complete randomness is the entire point of the mode. Anything that limits what heroes can pop up would make the mode meaningless. It’s about making the most of whatever crazy situation you’re in. That’s the whole appeal of the mode. I can also imagine the frustration people would feel when “Widow could blow this comp wide open but our Widow is terrible and runs away all the time so I’ll never get to be Widow since she’ll never take enough of a risk to ever die.”

Fun fact: if you kill their healer they are unlikely to respawn as one. Plus any of your crappy heroes that die in the process have a chance to change to something better. You can’t compare to any other mode without a healer because it stays that way all game. In MH, team composition is dynamic and managing it through targeting is a huge part of the mode.

I think hero stacking adds a fun layer to the game mode, but even if it got removed tomorrow, you’d still end up with some team comps that annihilate others, some that are perfectly chosen for the map they’re on, some where everyone gets one of their mains against a team full of people flailing on their worst heroes, a bunch of shields vs. weak shieldbreak, etc. etc.

There’s no way to make Mystery Heroes “fair,” because part of the fairness in Overwatch is the ability to meaningfully counterpick the enemy. Any time you don’t have control over your own comp, you run the risk of getting roflstomped by a team with better luck than you.

And it’s totally fine if that’s not your jam, but that means that no amount of changes to Mystery Hereos will make it your jam.